The National Institute on Deafness and Other Communication Disorders (NIDCD) supports research and development of innovative technologies for improving the quality and use of hearing aid devices. Physical Optics Corporation (POC) proposes the development of a new Ear Canal Optical Coherent Tomography (ECOCT) system to obtain the shape of the individual ear canal and the corresponding 3D image of the underlying tissue by a purely optical means, without taking an ear canal imprint. This innovative system will improve the accuracy of ear canal shape measurements (to better than 10 m) and provide a unique opportunity to use a 3D map of the underlying tissue to help eliminate excess pressure from the hearing aid shell impinging on the most sensitive areas in the ear canal. The digital file obtained by the ECOCT system will be sent to the hearing aid manufacturer through the Internet, and will be easily archived or stored on a personal memory stick. Manufacturing cost savings will be achieved through reduction of the shell rework to obtain a perfect fit into the ear canal. In Phase I, POC demonstrated the feasibility of the ECOCT concept by assembling a proof-of-concept prototype and demonstrating its performance with phantom ear models. The capabilities of the ECOCT system to measure the three-dimensional shapes and obtain mapping of the underlying tissue provides a strong foundation for the development of the Phase II prototype. The demonstration of the technologies in the course of Phase I show the feasibility of the successful development of a commercially viable system in the course of Phase II. In Phase II, POC will develop a fully operational device for digital mapping of the ear canal shape. The prototype will be tested with ear models at POC and then the operation of the prototype will be demonstrated with human subjects at the House Research Institute, Los Angeles, California. The performance of the ECOCT Phase II prototype will be evaluated against conventional ear canal impression techniques. Software will be developed for conversion of the ECOCT data into standard formats for custom hearing device manufacturing. The commercial viability of the ECOCT system will be evaluated in the course of Phase II and work will be initiated with potential partners for commercialization of the system. The fully developed ECOCT will provide a new rapid and more precise way of measuring ear canal shapes for custom fabrication of hearing aid devices. ECOCT technology will also be used for fabrication of individual noise protection devices for a wide variety of professionals (operators of heavy machinery, musicians, airport personnel, the military, etc.). Making individually fitted hearing protection devices will facilitate their acceptance by personnel while reducing cost, and will encourage employers to enforce their use by employees. As a result, less hearing loss effects will occur among American workers, which will have a significant impact on their quality of life.